First:
In the beginning of november 2012 Annelie will try to reclaim the Variable weight record.
During 2010 Annelie took the Variable weight record down to 126 meters. Down with a sled and up propelled by her monofin. This was done in the Red Sea in Sharm el sheik at the Only One apnea center. This autumn she is back in the Red sea on a boat looking for depth again. She is aiming for 130 meters.

If this record goes well and Annelie shows strength the team will move on to a No limit attempt. This will be done from a boat outside Sharm el Sheik. We will proceed with care due to the inherit risk in sleddiving. The discipline has seen some deaths and serious DCS and AIDA is no longer ratifying records (at least not now).

The planned No limit dive

The dive will be done with a so called sled.that travels along a rope down to 161 meters.

Down it will be dragged by led weights. Annelie will wear bifins that are fit into an aluminium box in a standing position. The stages of the dive are several. First it is important that she, during the breathe up, regulates carbon dioxide levels and maximizes oxygen supply. To much or too little breathing can lead to a failed dive. She will need a real full breath at the start. Even using a packing technique that enables her to squeeze more air into her lungs than a normal full breath.

Once the sled is released at her command speed is of importance. We want to minimize the dive time, oxygene must last for the predicted 3.30-4 min dive. It is also important that she spends as little time as possible to minimize risc of decompression sickness. We are aiming at a speed of more than 2.5 meters per second once the sled speeds up. Increasing pressure of the water masses will make equalization of the ear drums a challenge, specially at great speed. She will wear no mask as this is an air volume that would have had to be equalized, and thus air lost to the mask. She will be wearing a noseclip, wetsuit of 6mm thicknss and a smoothskin surface, and glasfibre bifins.

Annelie is good at equalization and her first problem will appear at 80 meters where she will have to switch eqalization method, no longer having acceess to air in the lungs. Her lung volume will when she passes 100 meters be less than one tenth of the volume at surface. She will fill her mouth and use that air for the remaining equaizations. Since the increase in pressure increases at a slower rate the deeper you go. It doubles the first 10 meters, but the inrcrease from 100 to 110 meter is only 1/10th. So one equalization of the ears at 120 may last to 135 meters. At these depths she will feel the pressure on throat and lungs (and all airfilled spaces). It will also be noticably darker and colder.

Relaxation is the key to oxygen conservation and will also reduce risc of damaging lungs. The increasing pressure can make the lung alveolis break. Many months preceding the attempts Annelie has worked with stretching and yoga techniques to prepare her for this attempt. Unfortunatly her in water training to essential depths has been fewer than hoped for. She is at the time of this writing still 35 meters away from her goal, 161 meters depth.

Doubts will be a component that can make her fail, so many factors has to work her way, not only what herself can control but the whole technical set up, the sea and the weather. Her task is during these three four minutes just to focus what is essential at the moment. She may have to break the sled again around 130-140 to deal with equalization, this will slow the dive down at a depth where speed is essential, every second spent below 100 meters will push nitrogen bubbles in her blood that can be life threatening. If the surface crew sees that she is far of the targeted dive profile, they may choose to abort the dive by starting a winch at the surface, pulling the line, bottom weight up, and eventually also the sled.

If speed is maintained and equalization works and Annelie is focused she will reach targeted depth withing 1 minute and 30 seconds. If the winsch will malfunction and anti ballast system can pull the whole system up. Weights dropped on the opposite side. Annelie herself will have 1 or even two ways she herself can return to the surface. Filling a liftbag with air (40 litres) or filling a life vest. Not much gear is built to function at 17 times the pressure at the surface. Many bold freedivers have died or been hurt for life in sled attempts, techical failure or bad planning (knowledge) and/or hybris has been some reasons.

The way up will be the easier part, feeling lungs expand again, light increasing, passing thermoclines and feeling water getting warmer. Tasting sucess. But just because she touched world record depth does not mean she has made it. She must at the surface be in such shape that she can, by herself, maintain airways above surface, make ok sign to cameras and say verbally that she is ok. The biggest risk the team must handle is DCS, decompression sickness (nitrogen buibbles in the blood that might expand and reach the brain). She will jump of the sled at about 30 meters and make a slow ascent, to help nitrogen bubbles expand slowly. She will after surfacing and the surface protocol then go directly to O2 breathing at a depth of 6-10 meters. This is to help nitrogen be vented out of her blood. Much of the performance lies in having gathered a team around her, created equipment that does the job, and prepared her body years in adavance. The dive itself, if she makes it, will feel relativly easy if everything falls into place.

Erika Shagatay (SWE) - scientist